I understand that pickle juice can also be prophylactic. You might try that as an experiment. About 3 oz. You're a big boy, you can deal with an astringent flavor. That's not a solution, just a maybe temporary palliative.
Low blood sugar can cause cramping, but that's really unusual during a 2-3 hour ride. It should be well known that hydration and electrolytes don't have much if anything to do with cramping, but bro-science persists.
You haven't done anything different with your saddle lately, have you?
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